Understanding what's in the foods you buy is key to stocking a nutritious kitchen. Yet food labels are not always easy to decipher. What exactly are you getting when you buy "juice," a "multigrain" bread, or a "low-fat food"?

Throw in terms like "fresh," "no additives," and "natural," and the confusion meter rises. Though they look good on packages, these terms aren't regulated, so they don't necessarily mean a food is better for you.

If you're confused by food labels, you're not alone. A 2005 survey by AJ Nielsen & Co. found that half of consumers understood nutrition labels only "in part," although 2 out of 10 said they consistently read them.

The secret to reading a food label is knowing what to look for. If you understand the label lingo, it's not so difficult to make the healthiest purchases.

The Essential Information

The most important and reliable information on the label can be found on the nutrition facts panel and the ingredient listing.

Here is the information that's most essential:

Calories. Despite all the talk about carbs and fat, calories are what counts for weight control. So the first thing to look for on a label is the number of calories per serving. The FDA's new Calories Count program aims to make calorie information on labels easier to find by putting it in larger, bolder type.

Serving size and number of servings per container. This information is critical to understanding everything else on the label. My daughter was horrified when she realized that the ice-cream sandwich she regularly ate had twice the calories she thought it did. Her confusion arose because some manufacturers take what most of us would consider a single-serve container and call it two servings, hoping the numbers on the label will look better to consumers.

Dietary Fiber. It helps fill you up, and you need at least 25 grams daily. To be considered high in fiber, a food must contain least 5 grams per serving. Fruits, vegetables, and whole grains provide fiber.

Fat. Fat has more calories per gram than carbs or protein, and all fats have 9 calories/gram. Choose unsaturated fats whenever possible, and limit foods with saturated and trans fats (also called trans fatty acids). Manufacturers are required to list the amount of trans fat per serving starting Jan. 1, 2006, and this information is already showing up on labels. In the meantime, look for terms such as "partially hydrogenated" or "hydrogenated," which indicate the product contains trans fats.

Sodium per serving. Sodium should be restricted to 2,300 mg per day (that's less than 1 teaspoon of salt) for healthy adults, and 1,500 mg for those with health problems or family histories of high blood pressure. To reduce your sodium intake, choose less processed foods.

Sugar. It adds plenty of calories, and is often listed on the label in "alias" terms, like "high fructose corn syrup," "dextrose," "invert sugar," "turbinado," etc. Choose foods with less than 5 grams per serving to help control calories.

% Daily Value (% DV). This reflects the percentage of a certain nutrient that the food supplies, based on a 2,000 calorie diet. It gives you a rough idea of the food's nutrient contribution to your diet. The nutrients highlighted in the % DV are a partial list, limited to those of concern to the typical American.

Ingredient List. Manufacturers are required to list all of the ingredients contained in the product by weight. A jar of tomato sauce with tomatoes as the first ingredient lets you know that tomatoes are the main ingredient. The spice or herb listed last is contained in the least amount. This information is critical for anyone who has allergies, and for prudent shoppers who want, say, more tomatoes than water, or whole grain as the leading ingredient.

The FDA sets specific rules for what food manufacturers can call "light," "low," "reduced," "free," and other food terms. Here's the low-down on interpreting these terms:

"Healthy" food must be low in fat, with limited cholesterol and sodium.

Anything labeled "free" must only contain tiny amounts of the ingredient in each serving. For example, "trans-fat free" or "fat-free" products can have only 0.5 mg of trans fats or fat; "cholesterol-free" foods can only have 2 milligrams of cholesterol and 2 grams of saturated fat.

A serving of a food labeled "low sodium" can have a maximum of 140 milligrams of sodium.

A serving of "low cholesterol" food can have a maximum of 20 milligrams of cholesterol and 2 grams of saturated fat.

One serving of a "low-fat" food can have a maximum of 3 grams of fat.

A serving of a "low-calorie" food can have a maximum of 40 calories.

A serving of a food labeled "reduced" must have 25% less of the ingredient (such as fat) than a serving of the regular version.

One serving of a "light" food must have 50% less fat or 1/3 fewer calories than the regular version.